Screen separator



March 9 1926.

J. F. ISBELL SCREEN snPARA'roR Fnduarch 9. 192s 2 Sheets-Sheet 1 Patented Mar. 9, 1926.

UNITED STATESY 1,576,430 PATENT OFFICE.

JOHN F. ISBELL, OF ALHAMBRA, CALIFORNIA; CLEMENTINEISBELL, ADMINISTRA- TRIX OF SAID JOI-IN F. ISBELL, IDECEASELD, ASSIGNOR OF ONE-HALF TO OTTO (al.l

BECKV/'ITI-I, OF LOS ANGELES, CALIFORNIA.

sonnen snPARATon.

To all whom t may concern.'

Be it known that I, JOHN F. IsnnLL, a citizen of the United States, and a resident of the city of Alhambra, county of Los Angeles, and State of` California, have invented new and useful Improvements in Screen Separators, of which the following is a specification.

In the present invention-hereinafter disclosed in its preferred specific embodiment--I have devised and perfected a screen separator, of the type commonly termed `in the art grizzlies or chain grizzlies, for separating and sizing ores, crushed rock, gravel and similar materials.

I have embodied in my invention certain principles of structure, the foremost object of which is to obviate possibility ofthe screen becoming clogged by` fragments wedging in the interstices; and, by eliminating clogging, or reducing it to a minimum, I accomplish lthe screening of the materials in a more rapid, efficient and economical manner.

My structural principle maybe embodied in either rotary or flat screens; may beused with equally good success for either wet or dry screening; and is adaptable to either light or heavy structures for handling materials ranging in size from comparatively fine to very heavy and coarse.

The salient features .of my invention will be more fully set forth in the following detailed disclosure7 which is to be taken -in connection with the accompanying drawings, illustrating the preferred form ofconstruction, and in which:

Fig. l is a side elevation illustrating vthe arrangement of the principles of my invention in a revolving screen;

Fig. 2 is an elevation of the feed end of the device illustrated in Fig. l;

Fig. 3 is an elevation of the discharge and driving end of the device, illustrated in Fig. I;

Fig. et is a transverse section, on a slightly enlarged scale, taken as indicated by the line Ll--a of Fig. l;

Fig. 5 is a fragmentary top plan view of my improved screen;

Fig. G is a transverse vertical section taken through the screen as indicated by the'line 6 6 on Fig. 5;

Fig. 7 is a fragmentary perspective. vieiv of my screen constructed as illustrated. in F igs. 5 and 6;

Fig. 8 is a slightly different form of construction of my screen; and

Fig. 9 is a side elevation of the arrangement shown in Fig. 8, being taken as indicated by the line 9--9 of that figure.

In perfecting this invention I have had in mind two desirable features which I have incorporated in my screen, these being- (l) the construction of a screen wherein possibility of clogging, resulting from fragfragmentary plan view of a.

ments of the material being screened lodging or wedging in the interstices, 'is `oloviated-or reduced to a minimum; and, (2) one which will be sufficiently durable in structure to handle all classes of materials, principally heavy materials, and which will withstand the severe wear and strain imposed upon creens of this type in the handling of the heavier materials. While the followingdetailed-disclosure will be directed to an eX- position of the preferred specific form of my invention, it is, nevertheless, to be understood that I reserve the right to make such changes or modifications in structure and arrangement as will properly come within the scope of the appended claims. l

In Figs. 1 to 4, inclusive, I have illust-rated the manner in which my structural principles may be embodied in a revolving screen;l while in Figs. 5 to 9, inclusive, I have illustrated the manner in which the same principles and arrangement of structuremay be embodied in a flat screen. In the former the material is caused to gravitate over the screen surface by its rotation, while in the latter its mobility may be induced either by jets of water or by longi- 16 and 17, reenforced by a peripheral, flange `lubly journalled in a suitable bearing 24,

also supported upon the frame 10. A ring gear is rigidly secured to the plate 21, concentric with the spindle 23, and is adapted to be engaged by an intermeshing pinion 26 rigidly mounted upon a drive shaft 27; the latter being revolubly journalled in a vsuitableA bearing 28 also supported upon the frame 10. Thus rotation of the shaft 27, will, through the medium ofthe pinion 26 and ring gear 23, effect rotation of the screen 11 in the direction indicated by the arrows in the several figures. The angle irons 14, which rigidly connect the rings 12 and 13 and support the screen 15,V are connected to the latter by seating in angularly-notched brackets 29 and 30, respectively, and to which the members 14 are rigidly secured, as by means of suitable bolts. Preferably the members 14 willv be mounted, relative to the rings 12 and 13, in

the manner illustrated in Fig. 4.

An imperforate metallic sleeve 31 may be secured to the flange 17, of the ring 12, to extend inwardly concentric therewith; and

Y through which the material to be screened may be fed to the screen 15. Tbe sleeve 31 also affords a means for washing the material before it is discharged onto the screen 15, to facilitate in its separation. As the I materials to bel separated pass overthe screen 15, the fines will bek separated and fall thfough the interstices and. be ydischarged through the bottom thereof, while the tailings or oversized materials will be "f discharged from the screen 15 intermediate its end and the ring 13, asindicated by arrows in I `ig.1.

In Fig. 4 I have illustrated the manner in whichthe principles ofy my invention are embodied in this type of revolving screen. In the first instance it will bepreferably made in the form of` individual rings 32, (either by casting or drop forging) having angular notches 33m their peripheries, re-

enforced by lateral flanges 34, which engage the members 14 for rigidly'holding them in place. It may be here noted that any number of the members 14 maybe used, depending upon the rigidity of the construction desired and the character of material the screen .is designed to handle, but for all practical purposes four ofthe members 14 will Ybe ample when disposed in the manner illustrated. This oifers the least possible lBores 36 are disposed at suit-able intervals around the rings 35, and, preferably, these bores will be surrounded by bosses 37, to extend beyond the opposite faces of he body portion 35, to act as spacers for the. latter when they are mounted upon the members 14, as illustrated in Fig. 1. When so mounted the rings will be rigidly held in juxtaposition by rods 33 extending through the bores 36 throughout the length of the screen.

The rings 32, being first formed as individual flat rings, are, when mounted upon the members 14, radially cut and their severed ends sprung over andv welded to the opposed similarly severed ends of the adjacent rings; so that when completed the screen 15 will be in the form of a continuous spiral. This spiral construction will conduce to movement of the tailings from the feed end to the discharge end of the screen when in operation without any. appreciable inclination of ythe latter.

A salient feature of my invention is the formation of a screen having a material supporting surface composed of a plurality of steps extending transverselyof the direction in which the material passes over it. The treads of these steps, or the surfaces upon which the material to be screened .is supported, are composed of a plurality of substantially parallel members having longitudinally vtapered ribs upon their top edges; the latterto form tapered intersticestherebetween, with the large ends of these interstices disposed towards the discharged end ofthe screen.

lIn the form illustrated inFig.' 4 the rings 35 forml what will be hereinafter termed the body portion, having its inner edge notched or serrated so that'when the rings 35 are joined together in jutaposition, as illustrated in Fig. 1, these serrated inner edges will form a plurality of steps extending throughout the length of the screen.- The material supporting surfaces of the step treads are formed by ribs 39, preferably integral with the rings 35; these ribs being longitudinally tapered so that when the rings are joined together there will be tapered interstices'bet-ween them. The ribs are so formed, relative to the rings, that when the latter are juxtaposed in ,operative relation their smaller tapered ends will be at the ydischarge edges of the steps, so the larger vends of the tapered interstices will also be at such discharged edges of the steps. The ribs 39. will preferably be cylindrical,

body portion 35; however, in some cases it [may only be necessary to make them semicylindrical, or they may have their top faces rounded, without departing from the principle of my invention. In any event, it is essential that the ribsk be wider than the body or supporting portions so that after the ines, as will be more fully later explained, pass between them their further discharge passage will be free and unobstructed.

In the operation of the revolving screen it will be rotated in the directipn indicated by the arrow A in Fig. 4, which will effeet the gravitation of the materials over the screening surface, as indicated by the smaller arrows B in that tigure. i

In Figs. 8 and 9, I have illustrated the flat screen embodying the same structural principles as shown in the construction of the revolving screen illustrated in Fig. 4. In this case the principle is identical, except that .the screen may be composed of a plurality of elongated body members a, each having a stepped material supporting sur- -face composed of tapered' ribs 39a formed on its top serrated edge. Transversely disposed apertures 3Ga are also provided in the members 35, in spaced relation, around which spacing bosses 37a are formed. Rods 38 also extend through the apertures 36a for holding the members 35el rigidly in juxtaposed relation. A. fiat screen, constructed as illustrated in Figs. 8 and 9, when in actual use will ordinarily be inclined so that the axes of the ribs 39a will extend substantially parallel to the horizontal.

The lengths of the members 35a and the size and spacing of the ribs 39a will be varied to suit conditions, which will ordinarily be determined by the character of the material the screen is designed to handle. Fig. 8 clearly illustrates the relative positions of themembers 35a and the ribs 39a, which form the steps; the arrows in that tigure indicating the direction in which the material passes thereover.k It can there be seen how the tapered ribs 39a, having their smaller ends disposed toward the discharge end of the screen, form tapered interstices therebetween. It may be here noted that the lengths of the ribs 39a forming the steps, may also be varied to suit conditions, as may also these portions of the serrated edges which form the step risers.

In` Figs. 5, 6, and 7, I have illustrated a slightly different form of construction, in which the screen is composed of a plurality of links, generally designated by the numeral 40. The lengths and size of these links.,

may be varied to suit circumstances, as above described, in connection with the members 351. HEach of thelinks 40 is composed of a Substantially flat body portion 35h having an upper inclined edge 41 upon which a sub stantially cylindrical tapered rib 391 is se-v cured; the latter preferably being formedV integral with the body portion 351. The upward inclination of the upper edge 4l, which carries the rib 39h, is toward the discharge end of the link; the rib 39 terminating at a slightly outwardly inclined shoulder 43. At the upper, or what might be termed the feed end of the link, a substantially cylindrical bearing portion 44 is formed with its axis extending at right angles to the axis of the body portion 35J and rib 39h, in which there is an axial bore 45. The width of the bearing portion 44 is preferably substantially twice that of the bodyy portion 35"; and the width of the large end of the rib 89", where it joins the bearing 44. is substantially the same as the latter. opposite or discharge end of the link terminates in a portion 46 extending slightly beyond1 the shoulder 43 and through which lthere is a transverse bore 47 axially parallel with the bore 45. In height the portion V46 is the same as the diameter of the bearing portion 44and is rounded at its end, as at 48, .to conform to the cylindrical conliguraf tion of the bearing portion 44, and is clearly illustrated in Fig. 7. The length of the portion 46 beyond the shoulder 43 may be varied to suit circumstances, but under ordinary conditions it will be of such length that when the materials are discharged from the ribs 39b they will normally drop onto the bearing portions 44, forming the next lower step, or onto the enlarged ends of the ribs 39h. Y

When formed into a screen the links present the appearance illustrated in Figs. 5, 6, and 7. They are joined in longitudinally offsety relation with the linksforining the next upper and lower steps, with the bearing portions l44 ofthe links `forming one step in transverse alinement with the ends 46 of the links forming the next step above and with the bores and 47 vof each in axial registration. Securing rods 49 are then extended through the registering bores 45 and 47 for rigidly. holding the links in this juxtaposed relation. The vscreen thus formed may be mounted in any suitable form of frame and tilted or positioned to suit thehandling of the Vvarious materials.

It is to be noted that the principal feature of my invention resides in providing a screen having a stepped material supporting surface which will obviate possibility of being clogged by the materials wedging in the interstices as they pass over it. This is accomplish-ed by first forming the material supporting surface of a plurality of longitudinally tapered ribs with their smaller ends disposed in the direction of the discharge edge of the screen. 'Ihese ribs are preferably rounded or made substantially cylin- The drical to reduce frictional resistance and facilitate in the rapid movementof the material thereover during the screening operation. However, it isnot absolutely essential to the success of my screen that these ribs be rounded at all, and where theyy are rounded it is not necessary that `they be substantially cylindrical, as the rounding 'oii" of their top edges in a semieylindrical form will accomplish the same results. But in the preferred form of my device I find the structure herein illustrated andy described gives extremely satisfactory results. It is very essential that the ribs be tapered smaller toward their discharge ends in order to form the tapered interstices: with their larger ends disposed in the direction of the discharge edge of the screen. vAnother feature of my invention is the disposition of the ribs in such a'inannerthat the materials discharged therefrom on each step will fall onto the enlarged ends of the ribs forming the next step below, which prevents the materials becoming wedged in the enlarged ends of the interstices v In the operation of the screen the materials are fed to the upper end, or in the case of the cylindrical screen hereinbefore described, at a feed end, and as theyvtravel over the steps which form the material supporting surface ofthe screen, moving from the largerv to the smaller ends of the ribs the fines or undersized materials will pass between the ribs and be discharged between the body portions which support the ribs. In this connection it is to be lnoted that with my particular structure the body portions form a rigid and unyielding support for the ribs which holds them in` absolutely fixed parallel alinement, and that after the fines have passed between the ribs the reduced body portions do not in any way interfere with their subsequent discharge.` In other words the substantially flat body'portions rigidly support the ribs, but do not interfere with the `discharge of the lines. The taper'- ing of the ribs 39 being smaller toward their discharge ends eliminates possibility of the materials binding in the interstices and conduces to continuous mobility of the materials thereover and their rapid and eicient separation.

As I have hereinbefore stated I reserve the right to make such changes or modifications in structure ofmy screen as will properly come within the scopeV of the appended claims. A number' of suoli modifications `maybe resorted to as, for instance, the

forming of the screen'froin a single sheetof metal, in which it is vexpanded to form the stepy material supporting surface having interstices therein tapered larger toward the discharge edges of the stepsand which may also be formed to present theV equivalent ofi thefrounded ribs SQhe-rei'nbefore described. It-'may even be practicable to construct my screen of the tapered ribs 39 without the use ofthe supporting body portions 35, as these are supplied for the purpose of giving great strengthand rigidity to the screen thereby conducing it to its long life and n adaptability of screening very heavy materials.

Having. described my invention, I claim:

f l. A rotary screen comprising a substantially tubular screen portion, means for rotatably mounting said, tubular member, said member `being composed of a plurality of spaced rings having serrated inner edges forming stepped material supporting surfaces extending longitudinally of the tube, and-tapered ribs on said edges forming tapered interstices therebetween.

Q .A rotaryY screen comprising a substantially tubular screen portion, means for rotatably mounting said tubular member, said membervbeing composed of a plurality of spaced rings. having serrated inn-er edges forming stepped material supporting surfaces extending longitudinally of the tube, and tapered ribson said edges forming tapered interstices therebetween, said ribs be- .ing tapered smaller and the interstices larger towards thek discharge edges of the steps. y

3. A rotary Ascreen comprising a substan tially tubular screen portion, means for ro tatably mounting said tubular member, said member being composed of a plurality of spaced rings having serrated inner edges forming steppedy material supporting surfaces extendingV longitudinally of the tube, each of said rings being joined to the neXt adjacent rings to form a continuous helix from end to end and tapered ribs on said stepped edges forming tapered interstices therebetween.

4l; A rotary screen comprising a base, spaced; end rings rotatably mounted on said base in substantially co-axial rel-ation, axially disposed brace members connecting said end rings, a substantially tubular screen portion supported between said end rings en said brace members. said screen portion being vformed of a plurality of axially spaced rings in the form of a-continuous helix, having serrated inner edges forming vstepped material supporting surfaces extending longitudinally of the tube, and ta pered ribs on said stepped edges forming tapered interstices therebetween, saidribs being tapered smaller and the interstices larger towards the discharge edges of the steps I In witness that I claim the foregoing I have hereunto subscribed my name this 26th day of January, 1923.

. Y JOHN F. ISBELL,

Certificate out (orreetioui.

lt is hereby Certified that the name of the assignee in Letters Patent No. 1,576,430, granted March 9, 1926, upon the application of John F. Ishell, of Alhambra, California, for an improvement in Screen Separators was erroneously Written and printed as Otto Q. B'eclmvith, Whereas said naine should have been' Written and printed as Otto Q. Beckworth, as shown by the records of assignments in this office;

and that the said Letters Patent should be read with this Correct-ion therein that the saune may Contorni to the record of the Case in the Patent O'Hice.

Signed and sealed this 13th day of April, A. D. 19216.

[SEAL] M. J. MO ORE,

Act/ing Uoqnmtssz'ofrter of Patents. 

